Apparatus for handling gases



Dec. 19, 1950 H. HOOPER 2,534,597

APPARATUS FOR HANDLING GASES Filed March 9, 1948 2 Sheets-Sheet 1 INVENTOR 2 HARRY HOOPER F BY 2 g M mdx ATTORNEYS Dec. 19, 1950 H. HOOPER 2,534,597

- APPARATUS FOR HANDLING GASES Filed March 9, 1948 2 Sheets-Sheet 2 FIG. 3

INVENTOR HA RRY H OOPER 7 BY J MWA SHW...

ATTORNEYS Patented a. 19, 1950 Reduction Company, Incorporated, New York, N. Y., a corporation of New York Application March 9; 1948, Serial No. 13,863

This invention relates to apparatus for heating gases, being adapted especially to the delivery of carbon dioxide gas from a higher to a lower pressure, although it may be used in dispensing gases other than carbon dioxide. In the dispensing oi carbon dioxide, pressure-reducing valves are employed in order to effect the necessary reduction of the pressure of the gas from that of the container in which it is shipped tothe pressure at which it is to be used. The cooling of the gas, due to expansion. often causes the formation of solid carbon dioxide and the freezing of precipitated moisture, which collects in the pressure-reducing valve and at the valve seat. Solid carbon dioxide and ice in the val e interfere with its operation and sometimes completely stop the gas flow. This d illculty can be obviated by warming the high pressure gas efore it reaches the pre ure-reducing valve. If there is a constant demand no diil'iculty is experienced becau e the heat ut can be re ulated readily so as to impart suilicient heat to the gas to prevent freezing without raising the temperature of the gas to a point wh re it is likely to dama e the internal arts of the pressure-reducing valve.

When the gas flow is not con tant, or the flow is at a low rate or is com letelv stormed for periods. the simple expedient ment oned is not satisfactory because the gas is certain to become o erheated at intervals with resu t n damage to the pressure-reducing valve. Moreover, overheating of the gas is undesirable becau e of its ineffic ency. In many a plications. the low pressure carbon diox de i d ssolved in water. and the solubility of carbon dioxide in water varies inver elv w th the temperature. Thus. ii the gas is heated materially above the minimum renuir'ed to prevent the formation of solid carbon dioxide or icev energv is wasted in heating the gas and a ain in cooling the water in which the gas is dissolved. It has been proposed heretofore .to heat carbon dioxide, prior to expansion, by passing it through coils submerged in a heated liquid bath. The amount of heat supplied to the bath is controlled by the rate of gas now. While the system is satisfactory under some conditions. it is not sufliciently flexible to follow very, wide or rapidly changing flow conditions. Since the heat is supplied indirectly to the gas through the liquid bath, there is an inherent time delay in its response.

An object of this invention is to provide a gas heating system of the demand type that will eiiiciently maintain a constant gas delivery temperature.

Another object is to provide a gas heater which reacts quickly to changes in rates of gas delivery and minimizes residual heating effects.

A further object is to provide a unit of the 1 Claim. (01. 62-4) is neat and compact in type described which well when structure and will function equally mounted in any position' 7 Another object is to provide a demand-type heater which responds to actual gas delivery temperature variations rather than flow variations, and which automatically compensates for extraneous temperature variations such as the temperature of the high pressure gas and the variations in atmospheric temperature surrounding the installation.

Another object is to provide an eillcient de-' mand-type heater in which the energyis introduced directly into the gas stream with very little heat loss to surrounding parts.

Other objects and advantages of the invention will be apparent as it is better understood by reference to the following specification and accompanying drawing, in which Fig. 1 is a plan view of an apparatus embodying the invention assembled with a pressurereducing valve of conventional design;

Fig. 2 isa view in elevation partly in section of the heater and pressure-reducing valve as shown in Fig. 1;

Fig. 3 is an enlarged sectional view of the heater on the line 33 of Fig. l; and

Fig. 4 is a diagram showing the electrical circuit employed.

Referring to the drawing, 5 indicates a pressure-reducing valve commonly called a regulator, in which the pressure of the entering gas is reduced to the desired point. The pressure reducing valve is of conventional design and need not be described in detail. Any of the commonly used types of pressure reducing valve may be employed in the apparatus. As is usual in such equipment, a pressure gauge 6 indicates the inlet pressure, and a pressure gauge 1 indicates the outlet pressure. The valve 5 is adjustable to permit the desired reduction of the pressure of gas flowing therethrough.

Supported on and connected to the pressurereducing valve is a casing 8 enclosing a heating chamber or passage M which has an inlet connection 9 for the gas at high pressure. The details of construction of the heater and of the regulator therefor will be described hereinafter. The gas, after entering the heating chamber, passes therethrough and escapes through a, passage to a pipe II which conveys it to the inlet connection I! of the pressure-reducing valve 5. The gas at low pressure escaping from the pressure-reducing valve 5 is withdrawn through a,

assess? Thus, all of the gas entering through the inlet 8 is subjected to heating to the required temperature. It expands in the pressure-reducing valve, the cooling eflect of expansion being compensated by the heat introduced to the gas. The temperature of the gas entering the chamber 25 regulates the temperature of the gas entering the chamber l4. Hence, regardless of varia-- tions in rates of flow there is always precisely the amount of heat input to balance the cooling effect of expansion, and there is no possibility of cooling the pressure-reducing 'valve to the point where solid carbon dioxide or ice may be formed therein. At the same time, overheating of the gas is avoided. If the outlet temperature of the gas drops, more heat is immediately supplied to the heating chamber. On the other hand, if the temperature of the outlet gas rises, heat is cut 011 in the heating chamber and the desired temperatures in the inlet and outlet gases are maintained substantially constant.

Referring to Figs. 3 and 4, within the heating chamber I4 is a core [6 of ceramic or other suitable insulating material which supports a heating element ll of high resistance conducting material such as is commonly used in electrical heaters, for example Nichrome wire. Of course,

platinum or any other metal having necessary resistance could be employed as the heating element. One lead I8 extends through a bore in the core l6, and the heating element I1 is disposed helically about the core, terminating in a lead 19. Conductors 20 and 2| extend through an insulating cap 22 which is secured in gastight relation at one end. of the chamber 8 by a cap 23. The other end of the chamber is closed by a plug 24.

inlet 9 longitudinally of the casing to the point where it escapes through the passage Ill.

Formed preferably in the same casing 8 is a regulator chamber 25, closed at one end by a plug 26 and at the other by a threaded nut 21. Within the chamber 25, a metallic sleeve 28 is supported by the nut 21. The lower end is closed by a wall 29. Mounted within the sleeve and supported at one end by a stud 30 and at the other by a stud 3| are flexed members 32 and 33, carrying contact members 34 and 35. The contact member 34 is connected to the conductor 2|, and the contact member is connected to a conductor 36. The conductors 20 and 36 terminate in a plug 31 which is connected to a source of current through a conductor 38. Thus the contacts 34 and 35 are in series in the electrical circuit, as shown more clearly in the diagram Fig. 4. When the temperature of the gas flowing about the sleeve 28 rises, the sleeve expands and the members 32 and 33 straighten until contact is broken between the contacts 34 and 35. This shuts off the supply of current to the heating element l'l. When the temperature of the gas falls, the sleeve 28 shrinks and the contacts 34 and 35 are again brought together, closing the circuit and thus supplying current to the heating element II. Consequently, any variation in the temperature of the outlet gas results promptly in modification of the amount of heat supplied to the incoming gas, and the temperature of There is suflicient space around the core It to permit the flow of gas from the' the outlet gas is thus maintained at a substantially uniform point and the temperature of the inlet gas is held to the point which compensates for the reduction of temperature due to expan sion when permitting cooling to the point where solid carbon dioxide or ice could form in the pressure-reducing valve.

While I have illustrated and described a particular form of thermostat adapted to regulate the amount of current supplied to the heating element l1, it is to be understood that any other efl'ective form of thermostat may be substituted therefor. It is necessary merely that the thermostat be sufllciently sensitive to variations of temperature in the outlet gas to ensure that the inlet gas is heated to the required temperature. Regardless of the rate of flow or intermittent stoppages of the flow oi the gas, the inlet gas will be heated sufliciently to accomplish the purpose of the invention.

Various changes may be made in the details of the construction and arrangement of the parts without departing from the invention or sacrificing the advantages thereof.

I claim:

An apparatus for delivering gases from a higher to a lower pressure including a pressurereducing valve, a casing having a plurality of longitudinal extending gas passages therein, an electrical resistance heater positioned in one of said passages for direct contact with gas flowing therethrough, thermostatic means positioned within a second of said passages responsive to the temperature of gas flowing therethrough to regulate the heating effect of said heater, means for introducing gas into one end of the passage containing the heater and means for discharging gas at the other end, whereby gas is caused to flow through said passage over and in contact with said heater, a passageway communicating at one end with the discharge end of the passage containing the heater, means for attaching said casing to said valve at the discharge end of said passageway, said attaching means having a passage therethrough for delivering gas from said passageway to the inlet side of said valve and a flexible conduit between the valve and the passage containing the thermostatic means for delivering gas from the discharge side of said valve into contact with the thermostatic means, whereby the temperature of gas delivered to said valve is maintained within predetermined limits.

HARRY HOOPER.

REFERENCES CITED The following references are of record in the flle of this patent:

UNITED STATES PATENTS Number Name Date 1,703,180 Smith Feb. 26, 1929 1,873,418 Jones Aug. 23, 1932 1,988,289 Wittemann Jan. 15, 1935 2,020,492 Zahm Nov. 12, 1935 2,221,077 Crowe Nov. 12, 1940 2,247,816 McIlrath July 1, 1941 2,365,526 Dean Dec. 19, 1944 

